While most people are busy relishing (or despising) fall, online retailers are busily planning for the annual onslaught of excited holiday- shoppers.

Last year, online holiday sales hit an all-time high, reaching more than $42 billion, according to comScore. This year, ecommerce software company Volusion predicts online holiday sales for small and midsize ecommerce merchants are projected to grow 20 percent.

Want to also see your sales similarly spike? Preparation and marketing will be key. Check out this month-by-month playbook for holiday ecommerce success:

October:

The holiday selling season starts as early as late October, so time is a ticking. To get started, use this month to create some important calendars and prep for search engine success.

-Build out your promotions schedule. The first step to your holiday plan is creating a promotions calendar. This document should be the basis of all activities you conduct throughout the holiday season, including specials and discounts you'll be offering and when. Don't forget to include major shopping holidays like Black Friday, Cyber Monday, Free Shipping Day and the week leading up to Christmas.

-Create your email calendar. Email is one of the most powerful tools in your online marketing arsenal, serving as a great way to deliver promotions directly to your customers. Your email calendar should include your strategy -- email content, list segmentation, copywriting, design and testing. To make the most of this opportunity, align your email sends with the timing of your biggest promotions.

-Shore up your holiday SEO efforts. Optimizing your site for search engines is a huge step to holiday success. If customers can't find your site in search results, they can't buy from you. To get started, tackle your on page optimization by updating all major landing pages with unique meta tags, or backend identifiers that help search engines find your page.

Also, ramp up engagement efforts, including getting more customer reviews by emailing clients for feedback, increase blogging efforts to get more links to your site and bump up social media.

-Create your design assets. While your homepage, email lists or banner ads won't have a festive look in October, you need to start planning on integrating a holiday feel into your look. Once you have your ideas in place, start the design work. Keep in mind if you're looking to professional design services for help, place your order now, to ensure they can accommodate you. By mid-October, holiday design strategy should be finalized and ready to implement.

-Plan for customer service. You're just weeks away from a big influx in customer service inquiries. Get ahead of the game by testing out your phone system, implementing live chat software and setting up autoresponders for appropriate email addresses.

-Prep for increased traffic. With a rise in shoppers comes a spike in traffic to your website. Ensure your hosting provider is equipped to handle this traffic influx and find ways to reduce your site's load time to keep customers from leaving your site before seeing it.

November/December:Once you hit November and December, it's crunch time. Your efforts should be laser-focused on converting customers and selling more.

-Blow out the major selling days. Cyber Monday and Black Friday are popular days for online buyers to make big purchases. This is also true in the two weeks leading up to Christmas, as last-minute shoppers are scrambling for those gifts. Ensure your marketing materials, discounts and featured products are visible to customers during these times.

-Keep tabs on inventory. Nothing is worse than telling a customer you're out of a product they really want. To prevent a bad customer experience, monitor your inventory levels so they meet demand.

-Show off your shipping. As the clock ticks closer to major holidays, ensure customers know your shipping policies. If it's December 22 and you offer two-day or overnight shipping, showcase it on your website -- customers will pay extra for the convenience.

-Don't stop with SEO. These efforts should never stop and neither should your attention to them. Keep optimizing your site for search engines.

-Take care of yourself. On top of managing your business during the holiday rush, you still need to make time for yourself and your loved ones. Even if it becomes overwhelming, don't forget to keep focus on your work-life balance.

For many online business owners, the holiday selling season can account for a big chunk of yearly sales, so don't let the opportunity pass you by. With this playbook in hand, you'll be in good shape to give yourself the greatest holiday gift of all: a boost to your bottom line.

What other suggestions do you have online retailers preparing for the holiday season? Let us know in the comments below.

Matt Winn

Matt Winn is Volusion's Marketing Communications Manager, where he helps oversee the organization's branding and communications efforts. Matt has created hundreds of articles, videos and seminars on all things ecommerce, ranging fro...